Evolution of Ionization-Induced Defects in GLPNP Bipolar Transistors at Different Temperatures

The evolution of ionizing radiation-induced defects in gated lateral p-n-p (GLPNP) bipolar transistors at different temperatures is investigated. The experimental results show that when the irradiation dose is less than 25 krad, the change in the reciprocal current gain (Δ(1/β)) increases by increasing the temperature gradually at a given dose. When the dose is more than 25 krad, Δ(1/β) increases first and then decreases at 200 °C by increasing the temperature at a given dose. Gate sweep (GS) technique and deep-level transient spectroscopy (DLTS) analyses show that the positive oxide trapped charges decrease by increasing the temperatures. When the temperature is less than 200 °C, the number of the interface traps gradually increases by increasing the temperature, but when the temperature increases to 200 °C, the number of the interface traps decreases. It indicates that the formation of the positive oxide trapped charges was inhibited at different temperatures above room temperature, and the formation of the interface traps was promoted at less than 200 °C and annealed significantly at 200 °C. Moreover, the change in the number of the interface traps in the transistors induced by the irradiation under different temperatures decides the degradation of the current gain.